The Study Of Ultrasound Coupled With Electrochemistry Degrading Organic Compounds In Coal Gasification Water

Phenol and pyridine were chosen as the representative refractory organics in coal gasfication water,and the feasibility of ultrasound/electrochemical method to degrade those compounds was studied in this paper.In order to analyze the senegistic effects between electrochemical method and ultrasound/electrochemical method,the effects of initial pH in solution,applied intensity of voltage,mass ratio of zero-valent iron(ZVI)to cyclinc activated carbon(CAC)and reaction time on removal ratio of phenol by electrochemical method and ultrasound/electrochemical method were studied.In addition,the action mechanism and the reaction dynamic models of degrading phenol by ultrasound/electrochemical method were investigated.Furthermore,the efficiency of ultrasound/electrochemical method degrading pyridine were conducted.The main content of experiment were shown as follows:(1)In order to confirm that the promotion effect of external electric field on micro-electrolysis reaction,the various forms of supplied voltage around micro-electrolysis filler were explored.The experiment results showed that the phenol removal ratio could be raised 28.73%with external electric field.(2)The removal ratio of stimulated phenol solution by different method,i.e.ultrasonic method,electrochemical method and ultrasound/electrochemical method,was conducted.The synergy factor(Syn)between ultrasonic and electrochemical method was calculated and the value was 98.02%.The data was a positive value and demonstrated that the synergistic effect between ultrasonic and electrochemical method was significant.(3)The effects of initial pH in solution,applied intensity of voltage,mass ratio of ZVI to CAC and time on phenol removal ratio by electrochemical method or ultrasound/electrochemical method were investigated.The maximum phenol removal ratio could be reached to 74.70%by electrochemical method,and 88.61%by ultrasound/electrochemical method.In addition,the results showed that all degradation process followed pseudo-second-order kinetic modols.(4)The GC-MS analysis was applied to investigate the organic compounds in effluent after the treatment by ultrasound/electrochemical method.The analysis results showed that phenol and pyridine was successfully degraded into micro-molecule which was easily degraded,which meant that the ultrasound/electrochemical method showed high efficiency in degrading aromatic hydrocarbon compounds,as well as heterocyclic compounds.(5)The SEM was used to characterize the stainless steel mesh(SSM),and the SEM,EDS and IR were applied to characterize the ZVI and CAC.The results showed that the SSM could be used long-term or recycled several times.The characterization results showed that the structure of SSM,ZVI and CAC were not changed by ultrasound/electrochemical method.The ZVI and CAC kept consuming during reaction process,and should be added at certain internal time in practical application.The experimental results suggested that electrochemical method assisted ultrasound was a feasible way to degrade organic matters,the biodegradability of coal gasification water was improved significantly,which provided foundation for following biochemical treatment to achieve standard charge.